How do you remove the headliner?

[AspiringOwner]

Two of my Wemac vents are not functioning. Borescope shows that the body that holds them apparently came undone from the headliner - I can look behind the headliner with a camera, rather than just into the air hose as in those vents that work properly.  Saw several posts with regard to the vents, but it seems my question may have been too simple to even address: How do you remove (or at least lower) the headliner to get access to the vents? There don't seem to be any fasteners...

[Marc_B]

You have to remove the seatbelt shoulder harnesses and sidewalls first then the screws are visible. The upper panels overlap the headliner.  There are some screws that have barrel washers as an offset.  The headliner is the first interior panel installed and the last to come off. 

Take plenty of pictures so you know how it all fits back together. It’s a game of Tetris and will be easier with a helper.

The material that Mooney used for the overhead ducts is thin and with age can come unglued at the longitudinal seam. They also used zip ties instead of cable clamps to attach the hose to the wemac elbow. So it may have just come off. But if you find the duct material needs replacing, do it now when you have your headliner down and be done with it. Otherwise it’s a PITA to go back and pull it all down again. 

[Slick Nick]

I also have two wemacs where the spring clips have come out. Looking at it, I believe it’s not “difficult” just time consuming. I’ve been putting it off for this reason, should probably get it done one of these bad weather weekends.